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gazzarda writes "The CBC is reporting that a team of Danish scientists are claiming that nerve impulses are transmitted by sound and not electricity. 'The common view that nerves transmit impulses through electricity is wrong and that they really transmit sound, according to a team of Danish scientists. The Copenhagen University researchers argue that biology and medical textbooks that say nerves relay electrical impulses from the brain to the rest of the body are incorrect.'"

There is only one real way to test this: put your head in a large bell and have someone ring it as loud as they can. If you lose all muscle control and are confused for a minute or so afterwards it would then prove that it is sound that controls nerves. Otherwise I suggest that we put a researcher in a specially made chair that will deliver high current directly through an electrode placed on the top of the head (and another somewhere else such as the wrists). If the researcher loses all muscle control then it also confirms that electricity controls nerves.

There is only one real way to test this: put your head in a large bell and have someone ring it as loud as they can. If you lose all muscle control and are confused for a minute or so afterwards it would then prove that it is sound that controls nerves.

That wouldn't prove sound controls nerves, for it is quite common knowledge that doing something like that would upset your middle ear, so you'd lose balance and become nauseous just because of that.

Well if you coat yourself with a conductive material, you would become in theory a sphere and thus have no electricity on the inside of the sphere. Not sure how much weaving and conductive stuff it would take to mostly negate the effect, but it could be done if it was done completely. Though if you make a capacitor vest and shock the bastard back... that'd be cooler and less practical.

You need to take "Logic 101" classes. Just because muscles react to electricity (and body transmits electricity) does not prove in any way that it is necessarily electricity that is used by body to control muscles. In the same way one can conclude that just becuase body reacts to bullets means that it uses bullets internally, which is nonsense.

The current bunch of moderators must have a horribly attenuated sense of humour.
This is the first slashdot post for months and months that actually made made me fully appreciate the meaning of 'LOL', because I did! Yet it gets scored +5 'Interesting', while hordes of pathetic little jibes get +5 funny. I just don't get what makes you lot tick.

And electro-shock, EEG's, retinal implants, and the old squid cell experiments where you stick electrodes in a squid neuron and measure its behavior are all based on a wrong theory, because the idiot who wrote The Fine Article can't figure out where the heat went from conduction of electricity in living matter? It's sitting inside a living organism with lots of *other* thermal processes going on: the heat generation is easily lost in the thermal noise.

I'll believe it when I see experimental evidence: but the article as presented is pretending that God makes timepieces himself because you found a watch in the desert. It's nonsense.

Slow down: The Hodgkins Huxley model of neural conduction is far too well supported by experiment, and by the observed behavior changes of nerve in response to ionic concentrations. You can't just throw that out due to a lack of thermal effects.Moreover, "heat produced by electrical conduction" and the like have to come from somewhere. The amount of energy processed by a cell is limited mostly by glucose metabolism. (We could chat about protein metabolism as well, but let's not get distracted.) That glucose

The story of the Brown Note, also known as the "Disco Dump," asserts the existence of a low frequency vibration which, when reproduced at sufficient volume, resonates with the depths of the human digestive tract to cause what medical personnel call "involuntary gastrointestinal motility." Put in less technical terms, the Brown Note reputedly precipitates a loss of sphincter control, giving rise to immediate defecation. Different versions of the myth place the freq

Really, man. If you've ever had problems with carpal tunnel syndrome and have been in to be properly diagnosed, you've had some neurologist stick needles into your arms and hands to measure the electrical potential traveling along the nerves of the arm from shoulder to hand.

I call bullshit, and I want whatever this group of Danish scientists are smoking. I'm betting trips to Amsterdam are de rigeur with these folks.

As a neuroscientist who has a healthy respect for a little anarchy from time to time, I have to call shenanigans on this one. I'd love to kick down the doors on some fundamentally held beliefs (my dissertation did something close to that), but this had me laughing out loud.

I've recorded from nerve cells in the classical manner and run the parametrics on different ionic concentrations and it would take quite a solid argument backed up by data for me to displace any of the credibility built on the classic Hodgkin and Huxley work.

Indeed, if it were true, I could shout at my hand and either I'd feel something or it would twitch or something. Sound waves permeate tissue way, way too easily to be isolated. This may be the most ludicrous article I've ever not read.:-D

If you know a member of the Academy, they can sponsor your paper and get it published in PNAS. I've read tons of bad articles in PNAS that got in that way.

And while much good research is published all over the place, this is so groundbreaking that it would be a Nature paper if good enough. Nature/Science/etc publish good, "exciting" papers. Other journals publish good papers that just aren't high-profile enough for the top impact journals.

I and my collegues did a research on the relationship between two distant methods of protein function regulation. We thought it was pretty nice, so we sent it to a bunch of very high-impact journals. Most of them sent it back even without giving it to referees. The only one that did refused us because we had a bad referee, and refused to even read our (long and detailed) response to his/her comments. So, less than year ago, we ultimately settled for a good but not top-most journal, where it was warmly accepted.

A couple of months ago my group leader talked at a conference in USA where he talked also about the research in that article. An editor of one of the journals we tried to publish that more than a year ago came to my boss and said "Really nice and hot work, why don't you publish it for us?" The answer: "Because you didn't want it a year ago, and now it's already done."

Why this sudden change? Because our proposed mechanism was not even a blip on the radar when we did it. In the meantime a recognized leader of the field published on Science a work that independently hinted in the same direction (even if in a very different and even less interesting way), and only because Mr.Guru created the buzzword now we are beginning to be taken seriously. Really sad.

Note: I think the main link in this thread has incorrectly summarized the article. I just read the original article and the headline is just plain wrong IMO. I tried to give my interpretation of this work here:

I will say that their physics seems reasonable - one should understand that when we say "sound" there can be several meanings to that word. In the article, they are talking about piezo-electric pulses which I can visualise as a pressure wave that creates voltages between synapses (forgive me if I'm murdering the biology here;-)). Imagine your usual piezo-crystal (a simple example is the one in a wristwatch) that vibrates (pressure waves) when a voltage is applied. Well, the reverse can also happen (this is used in some species of microphones). The way I visualize their model is that a piezo-electric soliton (if I remember my group theory, it's a sort of a quantized sound wave which persists without being destroyed by background noise because it has a topological quantum number asociated with it) travels between synapses leading to a voltage between them. Now, the pressure wave exists in the surrounding medium, which contains the ions in solution. So, at the most one can interpret these findings to mean that neural conduction is more like current in a superconducting wire than electroplating:D. This is the essence of their transport theory (as I understand it).

Another thing to note is that the article is not written as a maverick physicist would. It is written in a way that only a proper experimental physicist would - theory -> prediction -> experiment -> comparison. And the thing they are evaluating is actually the effect of anasthetics on neural transport. So, they are simply not claiming stuff as the news site falsely overhypes. I for one find this article fascinating even though biophysics is not my field.

I don't see how this translates to the sensationalist headline (although it's not the poster's fault, the linked site is a Canadian news site. The fact that it's Canadian is irrelevant:D, but the fact that it's a news site is rather telling. Also, they couldn't reach the authors for comments, which probably explains the awkward spin on the research.

IAAANS (I am also a neuroscientist) and I'm with you on this. TFA sounds pretty crackpot to me. If they really had strong evidence for this it would be published in Nature, not Biophysical Journal.

I'm afraid Nature is rather conservative in that respect and their editorial policy is at least partly based on maintaining or raising their impact factor (it is a highly profitable publication after all). The only way they can do that is by ensuring that only articles that are likely to be frequently cited in the future are published (that's the critical number that figures in the calculation of impact factor). As a result, the argument that any ground-breaking research would be automatically published in Nature is simply not true. Quite the contrary in fact. Now, before people mistake this for flamebait:P, I'm simply saying that Nature prefers the "wait-and-watch" routine, sorta like the Nobel committee, which is notorious for awarding A. Einstein with the prize for the photoelectric effect and not special or general relativity:P. I'm sure Nature will publish these guys a few years down the road after they have garnered enough of a reputation (IF they are correct that is!).

I was just trying to point out the decisions involved in publishing with Nature. If people want to publish something quickly that will spur interest and spawn more research in that particular area, they do NOT publish in Nature; rather they would publish in a more "everyday" journal like Biophys. A Nature publication (unless you research frogs; for some reason frogs are hot in NATURE =D) is sorta like a fine wine. You just can't afford to waste time on it everyday;). Plus, its rather dishearten

I agree that the article is being somewhat unfairly trashed. I did a significant part of my phd thesis work on channel biophysics, and some of the things they're saying aren't as ridiculous as they initially sound. First, they say that the HH model doesn't explain everything, and I think that's probably correct. However, it doesn't claim to. It contains a number of experimentally-determined parameters about kinetics and voltage-sensitivity of gating, and it doesn't say where those parameters come from.

TFA sounds pretty crackpot to me. If they really had strong evidence for this it would be published in Nature, not Biophysical Journal.

First, the Biophysical Journal is fairly respectable, and a much more appropriate place to publish work in this area. Second, the actual journal article in the Biophysical Journal does NOT say what the Slashdot and CBC titles say, so judging them on this basis is inappropriate. The article is an extension of a previously published model which shows that nerve signal propagation can be described as 100m/s piezo-electric soliton pulses, and it shows that these are dependent upon the phase transition temperatures for membranes.

Well, the one meter per hour figure refers to the drift velocity. The electrons aren't actually flowing like water in a stream, they are bouncing around like mad at speeds much faster than one meter per hour but they have a slight tendency to drift in the direction of higher voltage. Averaged out, this drift velocity is very small but the electrons themselves are moving much faster.

I think this is why so many people get confused by electricity. The FIELD moves almost the speed of light, but it makes electrons drift very slowly, even though the electrons THEMSELVES are moving rapidly. It's all very hard to visualize at first.

It's peculiar that neither of you "neuroscientists" took the opportunity to point out that neural signals are not electrical impulses--they're electrochemical state changes that propagate along nerve axons at a pretty sedate speed (measured in feet per seconds), and not any form of electrical current akin to what flows through a wire when you connect it across the poles of a battery (or pass the wire through a magnetic field, or whatever). The current in the wire travels quite a bit faster than 60 fps...

IAAP (I am a physicist) and an electical current is the movement of electrical charge. Consequently your "electrochemical state changes that propagate along nerve axons" are in fact electrical currents in the strictest sense of the word. When we have moving charge we have a current end of discussion.

The fact the propagation speed is much lower than when the electrical charge is an electron and the medium is a metal is entirely irrelevant. Lots of mediums exist that propagate electical current at much slower speeds than metals. I would also point out that propagation speed of an electrical current bears no relation to the velocity of the charge carriers either.

IANAPhy, but I study EM fiercely.Seems to me that when you said "in the strictest sense of the word" you put the word of the law above the math of the law. Since we're talking about a change in EM propagating through space we're dealing with AC rather than DC, and when dealing with AC we're dealing with the EM fields and not the charged particles mediating the fields. The EM fields of course move at c, and since the signals propagating through the nerves move a lot slower than that, we probably should concl

Absolutely incorrect. There is a reason that 'c' is called the "speed of light in vacuo". That reason is because a vacuum is the place where EM radiation travels that fast. In different media there is no requirement that the speed be this great. Indeed if you buy coax cable you will find that the rated signal speed is ~60-70% of 'c' although you can get special air-core cables with speeds of 80-90% 'c'. Clearly on a coax cable the signal is being transmitted by the EM field. Indeed there is a form of radiat

IAAPWASTEIBP (I am a physician with a sound training especially in basic physiology), and would like to comment that, while the particulars of HOW electric impulses are transmitted along nerves are not entirely relevant here, a simple test will prove THAT they are. AC current at low voltage. Touch it, see your muscles twitch, feel the paresthesia. As long as you can't explain how sound could do the same, I'll stick to currently accepted theory, thank you very much.

IAAN (I am a neuroscientist, yeah you knew that already) and, as they Physicist already explained, you are in fact describing electrical currents. So I agree with the other two neuroscientists, saying that the electrical models we have are wrong is just BS.

There are plenty of valid criticisms you can bring to the HH model. It cannot account for all observations (there was a paper in Nature recently exactly to this point) and after all, when you try to model primate cells with HH dynamics, you are in effect comparing your monkey with a giant squid! It has tbh always amazed me how well that worked at all. So if you're going to say, HH is inadequate, that's fair. If you are going to say that non-electrical pathways for transmitting information exist alongside the known electrical currents, that's also fair and you have my complete attention. But you can't just say that nerves don't use electricity, that just labels you as someone trying to be sensationalist. Besides, if you could prove this beyond reasonable doubt, you should and would send the paper to Nature.

Then again, this is my reaction to the/. summary above. I'd imagine the actual paper makes a more sensible argument, but I'm not going to read that before monday, so...

The Meyer Overton Hypothesis specifically relates to volatile (inhaled) anaesthetic agents, and NOT morphine which clearly has a receptor based mechanism of action. It's not correct to use the hypothesis for drugs such as opioids, or barbiturates (eg: thiopentone/pentobarbital), for which a receptor based mechanism of action has been established.

So, no, it doesn't predict the potency of most drugs, just the inhaled ones whose potency is directly proportional to solubility in octanol or olive oil.

As another neuroscientist, I would urge you to keep an open mind. Perhaps they mean the frequency of events fall neatly into the sound frequency range: i routinely see 20-200 Hz E/IPSC at RT, and much higher in larger neurons at 37'C. You can get action potentials at up to 1000 Hz in auditory neurons.If anything, try plugging in a speaker into your patch-clamp amplifier's audio port and see how it sounds (Back in the days I would directly convert the frequency and amplitude of the events in my voltage-clamp traces to raw PCM and play that out, and it sounded like some kind of a pothead techno mix tape, something you could definitely listen to and even enjoy.

Certainly, the movement of ions across the membranes is what drives most neurons (forgetting about the slower metabotropic communication, kinases, etc. for a second), but perhaps thinking of these in terms of frequencies would help non-math people appreciate the neuronal communication (the concept of a choir singing in a labyrinth is a lot easier to grasp for a layman than even the most basic HH multivariable d.-equation models).

There is a lot more information needed here. For those of you who haven't read the article, don't bother. Here is a summary: Some crackpots think neurons don't use electricity* because they don't get warm. Therefore, they use sound waves.
First of all, there appears to be no reason to suggest sound waves. Second, sound waves are not perfect transmitters of energy either. Some of it will bleed off as heat. So it seems to me that the very reason that they think it's not electricity* precludes it from b

... you can surely explain how anesthetics work, why the strengths of vastly different anesthetics seem to be solely determined by their membrane solubility (Meyer-Overton law), and why the effects of vastly different anesthetics can all be reversed by applying pressure, by lowering the temperature, or by lowering the pH?

Because all of that is explained by their model, as outlined in their first [pnas.org] and second [biophysj.org] articles.

I have a biology Ph. D. as well, and with some great neuroscientists in my department doing some cool electrophysiology stuff, this article seems crackpot to me at best, and total bullshit at worst (i.e. they're just spinning it differently to get some publicity).

To illustrate, his most compelling argument is this: "The physical laws of thermodynamics tell us that electrical impulses must produce heat as they travel along the nerve, but experiments find that no such heat is produced."

I thought nerve impulses were carried electrochemically by a wave of depolarizations? So not electrical as in signals on a computer bus (travelling close to the speed of light), but more like electrochemical waves (travelling much more slowly, like 120mph) - sort of like an electrochemical domino topple (well, except the dominos can right themselves afterwards). This is of course from school biology lessons, so I'm sure it's simplistic and probably mis-remembered.

I am currently in an Intro to Neuroscience class atm, but this sounds a bit...off. I am, obviously, not a scientist, but it seems to me that 1.)neurons and their associated structures do not have the physiological equipment necessary to produce sound, and 2.)Considering that the vast majority of passive and active scanning procedures specifically monitor or stimulate electrical activity in the brain, this seems a wee bit kooky. But, as stated, I ain't a scientist. Sage wisdom, folks?

I'm so tired of hearing the press use "scientists say" as a legitimizing opener. If you believe something because "scientists" say so, you are probably not a scientist. If you were, you would be forced to know many scientists who are idiots; scientists who no one should listen to.

Peer reviewed and agreed upon usually means good science. The CBC saying, "scientists say" means squatcum.

How do they explain all of the electrical measurements of nerve cells? We have measured voltages and currents. We know that these are dependent on certain protein channels, and salt concentrations. If impulses are actually the result of "solitons", how can they explain half a century worth of neurobiology? One wild guess, based on a minor inconsistency (if it even exists as they believe) needs a hell of a lot more evidence before they should be taken seriously.

"The CBC is reporting that a team of Danish scientists are claiming that telephone signals are transmitted by sound and not electricity. 'The common view that telephone wires transmit information through electricity is wrong and that they really transmit sound, according to a team of Danish scientists. The Copenhagen University researchers argue that telecom textbooks that say telephones relay electrical impulses from the source to the destination are incorrect.'"

Its very possible that neurons communicate using both electrical signals and sound solitons (and who knows what else?). If you play around with genetic algorithms or supercompilers you see that optimal solutions to problems often use unexpected mechanisms that defy logical analysys. We should expect to see this sort of efficiency in real evolved systems too.

On further review, it seems that the CBC article is total crap, but that the original paper [biophysj.org] isn't that far off the deep end. I admit that I don't know enough to really follow or critique the research, but it doesn't seem to be the crackpot theory that TFA implies. Nowhere, for example, does that paper say that nerves don't use electricity. In fact, the paper refers to "solitons" as a piezo-electric effect. They are merely proposing a new mechanism on top of previous theories, not trying to completely throw out all neuroscience to date.

To recap: Completely bogus headline, based on a completely bogus bit of popular science reporting, which itself is based on a possibly intriguing (but tentative) bit of original research. Nothing to see here.

BTW, IAANS (I am a neuroscientist). Here [pnas.org] is another link to their earlier research on this. While PNAS is certainly a reputable journal, I made some interesting observations while reading their paper:

(1) It's very physics- and modeling-heavy. While I don't like to generalize, my impression has always been that physicists are not very good biologists. I've been to many a "cross-disciplinary" seminars where physicists try to model biological processes, and inevitably they make very little biological sense.

(2) They cite mostly old papers from the literature (1960s) that point out deficiencies in the Hudgkin-Huxley model (although it's true that the HH model of action potential propagation may have become dogmatic).

(3) It was published via track I in PNAS, wherein a Member of the National Academy of Sciences can directly accept the paper for publication, bypassing peer review. The purpose of this mechanism is so that controversial works have a chance to be published; historically, it has been used to dole out favors and/or to publish crackpot theories.

Ultimately, while what they are proposing is not as crazy as TFA makes it out to be, the paper sounds to me that they are trying to make a mountain out of a molehill. Neuroscientists today have a very detailed understanding of how axonal neurotransmission works. The authors claim that the solitons (sound waves) in their model explain how nerve propagation in myelinated axons can be much faster than in equivalent non-myelinated axons, but again, neuroscientists are fairly sure they understand myelination in the context of the HH model. Even if axons go through soliton mediated pulses on the membrane that are in phase with action potentials (which is what they claim to observe), I seriously doubt that it has any physiological relevance, since just about everything neurons can do can be explained by ion flux through channels.

(1) Hodgkin and Huxley (1952) postulated the existence of transmembrane proteins that allowed conductance of ions in and out of the cell. They showed, using a giant squid axon, that action potentials are composed of a sodium current and a potassium current. While they had no way to directly observe the channels that allowed these currents to flow, using curve fitting, they worked out the general dynamics of these channels.

(2)
Sakmann and Neher (1976) [nih.gov] showed the existence of these channels by developing the whole-cell patch clamp technique. Single channels have been observed and characterized using this method (and employed by many labs).

(3) The term 'tranmission' is sometimes used in a confusing manner in neuroscience. In this case, as pointed out by the parent, transmission is down the axon of a single cell. Mylen sheaths can form around the axons of cells in order to speed up transmission. This can also occur by making the axon diameter wider. One interesting difference between vertebrates and invertebrates is that appearance of the mylen sheath with the advent of the backbone. This allows for cells to take up less space (so more can be packed into a given volume).

Another form of transmission of signal is between cells. This is usually done by chemical synapses. Chemical synapses work by the presynaptic cell releasing chemical into the synapse, the chemical ligand binding to receptors on the postsynaptic cell, and causing either an ionic flux (ionotopic channels) or a chemical cascade (metatrobic channels).

Somewhat recently there has also been discovered electrical synapses in the mammalian brain. These seem to be between inhibitory cells of the same type.

They wrote an article on their research in the previous edition of Gamma (the quarterly (IIRC) thingie about physics that's published at the Niels Bohr Institute at the University of Copenhagen (help me out here Danish physics students... I'm not too sure on the specifics of who is responsible and what its scope is))

that's not strange at all, especially if you don't know the pharmacological target of an anesthetic. Many lipids are used as chemical second messengers. There are many membrane bound proteins that might be a target.

IANANS (guess...) but I do find it very agreeable that it is odd that strength of an aneastaesia (yeah, it's misspelled) is proportional to its solubility in lipids if the inner workings of nerves are driven by electricity.

So you're willing to accept this on something as coincidental as the strength of a drug being proportional to its lipid-solubility? Wow.

Every cell in your body is encapsulated by a cell membrane that is essentially two layers of lipids. It's not a real revelation that many drugs' effe

And if you don't understand those tubes can be filled and if they are filled, when you put your message in, it gets in line and it's going to be delayed by anyone that puts into that tube enormous amounts of material, enormous amounts of material...

From what I vaguely remember of my artskool audio class, Sound at wavelengths of 5hz and below are more than capable of disrupting human thought. 10hz being the South Park "brown sound," which will disrupt the bowels (see also Transmetropolitan, etc).

Rephrasing the same statement three times is actually not the same thing as elaborating on it. Repeating something three times dos not provide more information. It's wrong to think that stating something three times over will make for a better summary.

The conduction of nerve impulses is understood at a detailed molecular level. There are numerous experiments that have observed everything from individual charges and ions traveling through channels and careful electrical modeling, to rationally designed anaesthetics that interact with specific molecules and targeted modifications of channels.

Now, it's always a good idea to keep an open mind. But these people have presented no even remotely interesting evidence that we need a change in paradigms. They are simply nuts.

If sound propagated down a nerve by sound, it'd end there. There's no mechanism to produce sound when a neurotransmitter from the first nerve mated with a receptor on the next.

Also, we listen to brain waves with an EEG or MEG, which measure minute electrical or magnetic impulses. We do not use a microphone and amplifier. Plus, we induce currents with electricity and magnetism, not loudspeakers, and produce predictable results.

Sound waves of sufficient intensity to propagate the full length of a nerve would be so strong in the main trunk that they'd disrupt the transport mechanism carrying neurotransmitters down from the cell body. They'd isloate the nerve from participating in the local neural network.

A new theory should explain everything just as well as the old plus more. This one falls apart at the basics and can't handle some of the nuances.

If sound propagation were the key, all that sodium and potassium gating to change the local membrane charge would be useless, and nature hates that kind of waste.

we listen to brain waves with an EEG or MEG, which measure minute electrical or magnetic impulses.

As a soliton travels down a membrane, the density and thickness change. Since the membrane is full of charged and polar molecules, changing its density and thickness will generate an electric signal that can be detected.

If sound propagation were the key, all that sodium and potassium gating to change the local membrane charge would be useless,

Just looking at the transmission speeds makes it clear what is going here:

Data:

electricity: thousands of km/sec in any medium

sound: several km/sec in dense media like intracellular fluid

neural transmissions: meassured at a few m/sec

Summary: neural transmission is orders of magnitude too slow to qualify as either an electrical or sonic phenomenon.

Conclusion: TFA suggests replacing one gross oversimplification of neural transmission with another. Neural transmission might have some qualities of both but is clearly neither. TFA is garbage.

Note Bene:There is no way of knowing what the original work was talking about. I cannot imagine anyone who has studied neural transmissions saying anything like TFA's contents. I suspect that the author of TFA was presented with an anology and took it for fact.

Never mind that, what about people getting ultrasounds? Expectant mothers getting scanned would be all over the place.Once, when I tore the ligaments in my hand, they went over the area with an ultrasonic gadget that was seriously ultra - it was in the 2 to 3 MHz range.

Surely either of those would have excited or swept past the frequency that nerves allegedly transmit at?